Casting metal alloys



July 20 1926.

CASTINGMETAL ALLOYS Filed Jan. 2, 1925 Patented July 20, 1926; n

* UNITED STATES PATENT OFFICE.

CASTING METAL ALLOYS.

Application led January 2,- 1925. Serial No. 198.'

Our invention relates tothe production,

alloys or mixtures ofvmetals by castin of which have a tendency tobecome segregated or disassociated when cooling -in the mold,

' ,5 such, for example, as copper and lead used in the manufacture ofbearings,ant1friction bushings, packing rings, and the like, and

one of the primary ob]ects of they invention is to provide a novelmethod of casting ario ticles of` this sort whereby the character of thesame is improved, particularly for anti-friction purposes, by making thealloy more uniform and homogeneous, through prevention of segregationand by more complete freedom from abrasivev impurities and from gasbubbles and other imperfections.

A further object is to provide certain novel apparatuses for carryingout the improved method.

A further object is to provide, as a new article of manufacture,anti-friction metal castings havin the hereinafter describedadvantageous c aracteristics.

The invention is illustratedin the accompanying drawings, wherein- Fig.1 is a sectional perspective view` of the metallic mold forming part ofa molding apparatus for the manufacture of i eomotive piston rod packingrings. n'

Fig. 2 is a view, in perspective, of the sand cope of this apparatus.

Fig. 3 is a similar view of the metallic` t I. sons which will appear,it is core.

Fig. 4 is a vertical sectional'view of the molding apparatus, theseparate lparts of which are shown in Figs. 1, 2 and 3, with said partsin assembled relation and the metal poured.

Fig. 5 is a sectional perspective of. the

acking ring cast in the apparatus shown in igs. l to 4 inclusivebefore'the `sprues have been removed. Fig. 6 is a view, insectionalperspective, of the metallic mold element of another form of apparatusfor casting. packing rings or the like. f

Fig. 7 is a vertical sectional view of the assembled apparatus` withthemetal poured.

Fig. 8 is a sectional perspective of the packing ring casting iii theapparatus of Figs. 6 and 7 before the sprue has been removed.

Fig. 9 is a view, in perspective,'of a metallic mold element forapparatus for casting cylindrical bushings.

the pouring gate or `than the .metal iii kthe` mold cavity,

Fig. l0 is la sectional perspective. of the copefor this apparatus.

Fig. 11 is a vertical sectional view 'of the` assembled apparatus.

Fig. l2 is a sectional perspective of the base member of the apparatus,and

Fig. 13 is a plan View of the collapsible metal core forming part of theapparatus of Figs. 9 to 12. y y l Y For packing the piston rods of steamengines operate by superlieated steam, it has een found necessary toprovide packing rings which will stand higher tempera-tures than thebabbitt'customarily used with engines operated by .saturated steam.

The packing rings should be made of anti friction metal or metals and analloy of copper and lead has been found suitable for the purpose exceptthat when the rings are cast in sand molds the cooling is so slow thatthere is a tendency for the metals to become segregated ordisassociated, the reason being, probably, that fused copper and leadform a yphysical mixture rather-thaman alloy in the strict sense of theword. Moreover, the sand is likely to be washed into theV castingforming slag, undesirable Vbecause .of its 'abrasive character, and gasholes in the castle have found that while it is not practical (at leastin the manufacture of cored castings) to use an all metal mold, forreapossible to efprevent the segregation-of the ingredient metals byusing a composite mold comprisingy metal mold and core elements betweenwhich the mold cavity is formed, and cope in which the pouring gates-arefectually arranged which is formed of molders sand.

Vlien the'k fused metal mixture reaches the mold cavity it cools sorapidly that disasysociation of the ingredient metals is prevented. Atthe same time there is considerable shrinkage, but to providel metal tofill the' cavity when this shrinkage takes place,

gates are filled or partially filled during the-pouring operation `andasV this excess met-al in the gates is in contact with sand, it coolsmuch more` slowly and will remain sufficiently fluent so asto flow downinto themold cavity to make up for shrinkage. If the `cope were of metalthe .pouring gate would be likely to` `freeze so as to make this operatiJn impossible. -Whle the :amount of metal necessary for making 4up forshrinkage may be small the volume in the-gates should be large enough toinsure against too rapid cooling. If an all-metal mold is emploved itwill be necessary to maintain theiuidity of the metal in the pouringgates by some other means, for -example, by pressure as in die casting.In order to prevent adherence of the casting to the metallic core it isdesirable, and in most cases necessary, to remove the core from theFahrenheit in order that the lead may not 4 sweat out. The casting ineither case is allowed to remain in finally set.y

Referring to Figs. l to 5 inclusive, 25

designates an annular cast iron mold elethe mold. until it' has mentforme'd, preferably, with a taperedv opening 26 and recessed at 27 toprovide, with the cast iron core 28, a cavity to receive vthe moltenmetali This cavity, in the form `of theapparatus shown in Figs. 1 to 4the conical surface, however, not extending quite to 'the inner edge ofthe mold element core 28 is tapered to fit the tapered openso that thisedge of the packing ring, indicated at 30, is blunt as shown at 31. The

ing 26 in member 25- and in assembling the parts .the upper edge' of thecore is flush with the upper edge of element 25; The

mold cavity is covered by a green sand cope 32 formed withapouringopening and a riser designated 33 and 34. The metal oured into the moldcavity through one. o these openings will, of course, rise in the otherto the extent of excess of metal over that necessary to ll the cavity.The metal in the cavity chills rapidly and shrinks. The metal inopenings33, 34 cools 'much more slowly so that it will remain fluent andwill flow into the cavity to'make u for the shrinkage of the metaltherein.- s soon as the metal has hardened but before it has taken itsfinal set, the cope is removed and the metal core is knocked out. Whenthe casting has set it is removed. from the mold element 25, after whichthe sprucs 35 36 are cut off and the surfacesgof the ring finished asmay be necessary. We have found that there is little or no Washing ofthesand o f lmingling of sand with metal took place, with rom the cope'into the casting. The interthe old' method of sand. molding, largelywhen the hot metal struck the sand bottom of the mold cavity, The sandcope-permits the ready escape of gases from the mold cavity. If desiredthe castingmay be gated to direct impingement of the molten metalagainst the wall of the mold.

The preferred-ingredients for a packing ring to be used as indicated,are as follows: 35%l to 40% copper, 3% to 5% nickel,the balancelead. Thenickel gives a more intimate amalgamation of the other metals.Preferably we use a flux consisting of phosphor copper v(85% copper and15% -phosphorous). This ux is used in quantities of from 1 to 4 ouncesper 100 pounds of metal.

It acts as a dioxidizer so. that the metal flows more freely.

The same method may be used for casting any unstabley mixture of metals,such, forexample, as a mixture of 68% copper, 25% lead and 7% tin.

In Figs. 6, 7 and 8 wehave illustratedla modified, and in some respectsmore desirable method of casting' the .same sort of packing ring orother like article. In this apparatus the cast iron mold element 37 isarranged, in a position inverted with respectvl to that of .element 25,upon an iron base plate 38. The metallic core 39 is annular in form butexternally tapered as is core 28. Within the metal core 39 is a dry sanda core 40-which is formed with a pouring gate converges downwardly aslndicated at 29,.

41 and projects up through :the green sand cope 42. An orifice 43through the sand and metal cores leads to the mold cavity 44. The moldelement 37 is formed with a plurality of gas orifices 45 to allow escapeof gas from the mold cavity into the green sand of the cope. This lformof casting ap aratus has the. advantage that the wide end 45`of thepacking ring 47 (Fig. 8) has a relatively smooth surface requiring butlittle finishing. Vvrhatever slag there may be in the metal collects inthe tapered end of the ring from which it may be removed by a simplifiedmachining operation. When the castin' has sufficiently set the cope 42is remove and the mold 37, core 39 and the casting are inverted and thecore knocked out of the mold element 37 from which the casting may thenbe removed and its sprue 48 cut pif.

In Figs. 1 0 to 12, I have shown apparatus for casting the1 cylindricalbushing designated 49. A suitable alloy for an anti- Irietion bushing ofthis sort consists of copper, 5% tin and 25% lead. These metals tend tosegregate when cast in sand. The molding apparatus comprises separablemetallic mold members 51, 52 adapted to be secured together by bolts 53,a metal base .and l'adapted to alignv with the mold cav ity between moldelements 51, 52 and the core. The core is madel preferably'in threeparts 56, 57, 58, as shown in Fi 18,' part 58 being a Wedge which can bereadily knocked out when the corel is to be removed. For this purposethe core sections V are formed with recesses 62 for a chisel. The coreis removed while the casting is hot. After the casting is set it may beremoved from the mold. The embodiment of the invention disclosed inFigs. 10 to 12 is not claimed in its specic details in this applicationas it forms part of the subject matter of any application by us, SerialNo. 111,993, filed May 27, 1926 as a continuation in part of this`application. p

It will be understood that the apparatuses and methods described are, sofar as details are concerned,.merely illustrative of the principles ofour invention Which4 We propose to claim as broadly as the state of theart will Warrant.

We claim:

1. Molding apparatus for casting metal through,

' ing alloys of the character described, comprising, in combination, ametallic mold element having a tapered opening therein, a taperedmetallic core to fit into said opening, and a sand element formed with apouring gate leading to the cavity between said mold element and core.

2. Molding apparatus for casting metal alloys of the characterdescribed, comprising, in combination, an annular metallic mold element,the opening through which is tapered, a tapered metallic core to fitinto said opening, and a sand cope provided with a pouring gate leadingto the mold cavity.

3. Molding apparatus :for casting metal alloys of the characterdescribed, comprising, in combination, an annular metallic mold elementhaving an opening therea metallic core to fit into said openand '1 sandcope provided with a pourgate leading to the mold cavity.

WiLiiniivi H. onori?. ROBERT JTSHOEMAKER.

ing,

